The invention to be described herein relates especially to gas separators for use with submersible well pumps and especially to those which are used to pump oil from deep wells. About seventy-five percent of pumps sold annually in the United States for pumping oil from deep wells are equipped with some form of gas-oil separators, because pumps cannot effectively handle oil containing large quantities of gas. Many oil wells exist which have gas-oil ratios too high to economically produce oil at this time. In the Middle East, gas-oil ratios are high and, production rates are also high. To improve the production of gas-free oil, and to permit the economical production of oil from some wells in the United States, especially in these times when there is a serious energy crisis and where it is prudent to be self-supporting in the production of oil, the concept of using a separator to supply gas free oil to a pump in wells in which the gas-oil ratio is high becomes extremely important.
The prior art types of gas-oil separators are generally not entirely successful in providing a substantially gas-free product.
One of the problems encountered in submersible well pumps is that of geometry; i.e., the size of the device is restricted to the size parameters of such pumping devices, which may vary in diameter from about 4 inches to about 63/4 inches to be used in well casings which may vary from 41/2 inches to 8-55/8 inches in diameter. These pump assemblies may have a length, including the motor and usual seal section of approximately ten to thirty feet or more. The separator, to be functional, must be included within these parameters and within the diameter of the pump assembly.
Other types of gas separators are known in the art; usually they are not for use in down hole applications. They use porous members or filters placed in the flow stream which do not permit gas to pass; the gas is removed via a vent. All or parts of such filters may be wetted by the liquid. In order to prevent gas blockage of some filters, the filter element is constructed with both liquid wetted and liquid repellent parts. The liquid wetted parts will pass the liquid; the liquid-repellent parts will not be wetted by liquid and will remain open for the passage of gas.